how is this?

[Serum]

And do you find an unbalance in discharging? with a 7.2 V discharge and an unblance, you might also drain a cell lower than the .6 volts

[Rtsbasic]

Fast discharging at 10 amps down to 0.9v/cell doesn't actually bring the nominal voltage that low. A cells voltage may be 0.9v at 10 amps, but at 2 amps its closer to 1.1v. I have had no problems or unbalanced packs using this method for several months now on both matched and unmatched/very low packs. In the UK this is the most common method of looking after cells when racing I have observed, the biggest variation is if you equalise after fast discharge, or just before recharging, I do it just before recharging.

Contrary to what a lot of people say, you can take NIMH's below 0.5v/cell or even dead short them, if you start doing it while they're new, otherwise they don't take to it well. Doing this shortens their life and runtime but does give a noticable increase in punch.

If the cells were that unbalanced that one cell can be 0.9v and another 0.2v causing damage the packs not likely to be any good anyway. I personally haven't seen this much variance in cells even on packs that have been abused on a pulse charger for over a year.

[Serum]

Okay, thanks for that info!

The method you are using (staying above .5 volts each cell) doesn't affect the capacity nor it's lifespan? that .6 volt discharger simple are a few diodes i presume? You could easely make it yourself! Guess i'm in the race for some serious resistors to discharge a 16-20 cell pack with 10A... only downside is that you need to replace the heatshrink more often..

[Rtsbasic]

No problem mate.

Discharging to 0.6v/cell is perfect and doesn't affect the capacity nor the lifespan. The tray I use does indeed use a diode with a resistor, and some bits for an LED to tell you when its done. Easily made, check out http://www.schumacher.clara.net/equaliser.htm for a basic diagram, and a link on how to add status led's to it.

I've never needed to replace the heatshrink on my cells due to charging/discharging, I don't understand why you'd need to? As your only going to 0.9v with 10 amps you aren't heating the cells that much, and most tray's to equalise at 0.6v start at 3 amp and get lower the lower the voltage goes, so doesn't make the cells more than warm.

EDIT: Unless you mean pack heatshrink, I was referring to cell heatshrink, I never use pack heatshrink anyway and just run some tape around the middle of the cells and a bit of glue between each cell to hold the packs together. I have yet to short out a pack in a car doing this, you just have to be careful.

[Serum]

Yeah, that edit was what i was talking about. ;)

I will make one of those things, i thought they are forbidden for nimhs and they are meant for nicd's, i will try it for sure! (one of the myths about nimh i think)

Only need to find a nifty way to discharge the cells at 10-11A and make a cutoff at the desired voltage. Can't be that hard..

[Rtsbasic]

Its a myth that you can't use a tray with NIMH's. You shouldn't use NiCD trays with NIMH's because NiCd ones cut off a lot lower which will harm NIMH's.

Some people use a series of lightbulbs with a diode to cut off as a fast discharger, make sure you put a cut off in place if you do that though as if you take a NIMH to 0.6v at 10 amps you may harm it.